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<a name="169208726"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/blog%20posts/near/169208726" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/blog.20posts.html#169208726">(Jun 28 2019 at 08:57)</a>:</h4>
<p>Hey <span class="user-group-mention" data-user-group-id="491">@WG-nll</span> , just wanted to point you all at a blog post I put up last night that tries to enumerate all the ways that NLL is going to "break" peoples code: <a href="http://blog.pnkfx.org/blog/2019/06/26/breaking-news-non-lexical-lifetimes-arrives-for-everyone/" target="_blank" title="http://blog.pnkfx.org/blog/2019/06/26/breaking-news-non-lexical-lifetimes-arrives-for-everyone/">Breaking News: Non-Lexical Lifetimes Arrives for Everyone</a></p>



<a name="169208794"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/blog%20posts/near/169208794" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> lqd <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/blog.20posts.html#169208794">(Jun 28 2019 at 08:58)</a>:</h4>
<p>it looks awesome Felix, great job</p>



<a name="169208822"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/blog%20posts/near/169208822" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/blog.20posts.html#169208822">(Jun 28 2019 at 08:58)</a>:</h4>
<p>Thanks; those gists you made <span class="user-mention" data-user-id="116113">@lqd</span> summarizing the output from the crater runs were a huge help</p>



<a name="169208838"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/blog%20posts/near/169208838" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/blog.20posts.html#169208838">(Jun 28 2019 at 08:59)</a>:</h4>
<p>(because I strived to include examples that were reduced from actual regressions that I could point to)</p>



<a name="169208862"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/blog%20posts/near/169208862" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> lqd <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/blog.20posts.html#169208862">(Jun 28 2019 at 08:59)</a>:</h4>
<p>I wish (and have vague plans) for a tool to help us categorize crater results much like you did in the spreadsheet</p>



<a name="169208922"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/blog%20posts/near/169208922" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/blog.20posts.html#169208922">(Jun 28 2019 at 09:00)</a>:</h4>
<p>Such a tool, if made general purpose, could indeed be quite useful</p>



<a name="169208925"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/blog%20posts/near/169208925" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/blog.20posts.html#169208925">(Jun 28 2019 at 09:00)</a>:</h4>
<p>it was super painful doing that by hand.</p>



<a name="169208938"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/blog%20posts/near/169208938" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> lqd <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/blog.20posts.html#169208938">(Jun 28 2019 at 09:00)</a>:</h4>
<p>I think mark recently did a bunch of work in this similar direction for the recent beta regressions</p>



<a name="169209015"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/blog%20posts/near/169209015" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> lqd <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/blog.20posts.html#169209015">(Jun 28 2019 at 09:02)</a>:</h4>
<p>thankfully it's not that often that we have to run through so many "regressions" :)</p>



<a name="169209201"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/blog%20posts/near/169209201" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> davidtwco <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/blog.20posts.html#169209201">(Jun 28 2019 at 09:05)</a>:</h4>
<p>That's an excellent post <span class="user-mention" data-user-id="116083">@pnkfelix</span>, really exciting to see migrate mode enabled for 2015.</p>



<a name="169214249"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/blog%20posts/near/169214249" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> lqd <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/blog.20posts.html#169214249">(Jun 28 2019 at 10:40)</a>:</h4>
<p>(also, thank you for the classy shout-out to the WG at the end of the post :)</p>



<a name="169273429"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/blog%20posts/near/169273429" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> simulacrum <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/blog.20posts.html#169273429">(Jun 29 2019 at 00:18)</a>:</h4>
<blockquote>
<p>I think mark recently did a bunch of work in this similar direction for the recent beta regressions</p>
</blockquote>
<p>My tool mostly just eliminates the "this crate isn't actually the root cause" -- i.e., when a dep fails to compile -- by grouping</p>



<a name="169273692"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/blog%20posts/near/169273692" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> simulacrum <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/blog.20posts.html#169273692">(Jun 29 2019 at 00:25)</a>:</h4>
<p><span class="user-mention" data-user-id="116083">@pnkfelix</span> fwiw, I found the liveness check section a bit confusing -- it looked initially like <code>T::Type</code> should play some role since it's there, but it can actually be simplified to <a href="https://play.rust-lang.org/?version=stable&amp;mode=debug&amp;edition=2018&amp;gist=c81fab3a3678e5ed1e31c6860ab02741" target="_blank" title="https://play.rust-lang.org/?version=stable&amp;mode=debug&amp;edition=2018&amp;gist=c81fab3a3678e5ed1e31c6860ab02741">this</a>. Great post overall though, good job!</p>



<a name="169282799"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/blog%20posts/near/169282799" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/blog.20posts.html#169282799">(Jun 29 2019 at 05:24)</a>:</h4>
<p>You’re right; that might have been something we fixed about <code>impl Trait</code> in MIR borrow-check. Not sure if that needs it’s own section (and a different example for the licenses check). Was too tired to properly verify when I wrote that part</p>



<a name="169282808"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/blog%20posts/near/169282808" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/blog.20posts.html#169282808">(Jun 29 2019 at 05:24)</a>:</h4>
<p>*liveness, not “licenses”</p>



<a name="169296245"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/blog%20posts/near/169296245" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> simulacrum <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/blog.20posts.html#169296245">(Jun 29 2019 at 12:55)</a>:</h4>
<p>no worries</p>



<hr><p>Last updated: Aug 07 2021 at 22:04 UTC</p>
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